PerfData counter: sun.gc.policy.generations in JDK 8

Stefan Karlsson stefan.karlsson at oracle.com
Fri Apr 15 13:43:28 UTC 2016


Hi Ramki and Jon,

What's the status of this review thread? The bug is still open and 
targeted for JDK 9.

Thanks,
StefanK

On 2015-06-03 08:15, Srinivas Ramakrishna wrote:
> Thanks Jon for the review and the pointer to the test. I'll get back 
> to you later this week with a suitable test.
>
> -- Ramki
>
> ysr1729
>
> On Jun 2, 2015, at 14:16, Jon Masamitsu <jon.masamitsu at oracle.com 
> <mailto:jon.masamitsu at oracle.com>> wrote:
>
>> Ramki,
>>
>> Changes look good.
>>
>> I'm guessing you tested by generating the
>> perfdata by hand and verifying the contents
>> of the perfdata.  Do you think a test can
>> be written to verify  the change?  If you look at
>>
>> test/gc/metaspace/TestMetaspacePerfCounters.java
>>
>> in your repository I think that is an example that
>> can be followed.
>>
>> It's a jtreg test.
>>
>> http://openjdk.java.net/jtreg/
>>
>> Jon
>>
>> On 06/01/2015 11:39 AM, Srinivas Ramakrishna wrote:
>>> Thanks for the review of the patch for 8-dev (from the ticket), 
>>> Staffan.
>>>
>>> Sorry for the delay in getting the official webrev out -- it took me 
>>> a while to first get set up with an hs9 repo (thanks Jon!) and then 
>>> get my openjdk credentials updated (thanks Mark!).
>>>
>>> Here's the webrev against hs9 for official review:-
>>>
>>> http://cr.openjdk.java.net/~ysr/JDK-8080345/webrev.00/ 
>>> <http://cr.openjdk.java.net/%7Eysr/JDK-8080345/webrev.00/>
>>>
>>> I built and tested the change (on both 8-dev whose patch was 
>>> attached with the original bug, as well as this with hs9) and 
>>> verified that the counter value for generations, in the perfdata 
>>> file, was now 2 instead of the previous 3.
>>>
>>> thanks!
>>> -- ramki
>>>
>>>
>>> On Mon, May 18, 2015 at 1:22 AM, Staffan Larsen 
>>> <staffan.larsen at oracle.com <mailto:staffan.larsen at oracle.com>> wrote:
>>>
>>>     Looks like a good patch to me.
>>>
>>>     /Staffan
>>>
>>>>     On 14 maj 2015, at 18:12, Srinivas Ramakrishna
>>>>     <ysr1729 at gmail.com <mailto:ysr1729 at gmail.com>> wrote:
>>>>
>>>>     https://bugs.openjdk.java.net/browse/JDK-8080345
>>>>
>>>>
>>>>
>>>>     On Wed, May 13, 2015 at 1:08 PM, Srinivas Ramakrishna
>>>>     <ysr1729 at gmail.com <mailto:ysr1729 at gmail.com>> wrote:
>>>>
>>>>
>>>>         With perm gen going away (and being replaced by metaspace)
>>>>         in JDK 8, it makes sense that the counter
>>>>         sun.gc.policy.generations should be "2", rather than "3".
>>>>         However, in JDK 8 that counter still says 3.
>>>>         As I understand, the intention was that this counter would
>>>>         allow you to (for example) know the range of
>>>>         the sun.gc.generation.$num.* counters describing each of
>>>>         $num < sun.gc.policy.generations in the heap.
>>>>         Recall that the erstwhile perm gen in JDK 7 used to be
>>>>         synonymous with sun.gc.generation.2, but the
>>>>         JDK 8 avatars are now sun.gc.metaspace and
>>>>         sun.gc.compressedclassspace.
>>>>
>>>>         The fix is simple, and I can submit a patch. Is there an
>>>>         existing bug for this?
>>>>
>>>>         thanks!
>>>>         -- ramki
>>>>
>>>>
>>>
>>>
>>

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